Investigation on the effect of SiC and TiB2 ceramic particles on mechanical and tribological properties of Al7075 hybrid metal matrix composites prepared through conventional stir casting technique

Abstract

Materials with lightweight construction, high strength and wear resistance are preferred in the automotive sector and aluminium is found to be a natural choice for the manufacturers. In this work, Al7075 hybrid metal matrix composites enhanced with SiC (6% weight fraction) and TiB2 (2%–6% weight fraction) particles were fabricated by stir casting technique. The characterisation of internal structure of the developed composites was done by subjecting them to scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS). It was found that the reinforced particles were uniformly distributed in the aluminium matrix alloy, and only a few clusters were found in the matrix alloyed with 6% TiB2. The tensile strength, hardness and flexural strength of the hybrid composites increased with increase in the weight percentage of reinforcements and attained a maximum of 233.34 MPa, 220 Hv and 458 MPa, respectively, when reinforced with a maximum of 6% SiC and 6% TiB2. The elongation percentage and the impact strength of the hybrid composites start to decrease with an increase in reinforcement percentage and attained a minimum of 6.74% and 1.2 J, respectively, when reinforced with a maximum of 6% SiC and 6% TiB2. By adjusting the input parameters such as load, sliding speed, and sliding distance, the sliding wear behaviour of the hybrid metal matrix composites was explored. It was discovered that the wear rates and coefficient of friction of the hybrid composites decreased with an increase in reinforcement percent. As a result of exhibiting superior mechanical and tribological capabilities, the results show that Al7075 with 6 wt.% SiC and 6 wt.% TiB2 hybrid composite performs the best over all other hybrid composites.